Image orthorectification method for fisheye camera

Abstract

The invention discloses an image orthorectification method for a fisheye camera. The method comprises the following implementation steps: firstly, establishing an indoor three-dimensional calibration field, establishing a free coordinate system, measuring three-dimensional space coordinates of artificial identification points, and acquiring an original fisheye image; calculating an image principal point and a camera focal length initial value, and performing coordinate transformation on an original image in combination with the spherical perspective model to remove spherical distortion; then constructing a fisheye camera optical distortion model, introducing the model into a direct linear transformation (DLT) model to obtain the fisheye camera optical distortion model, and solving an optical distortion coefficient and internal and external orientation elements of the original image; and finally, starting from a collinear conditional expression, carrying out ortho-rectification on the perspective image without spherical distortion by adopting indirect digital differential rectification to obtain a calibration field ortho-image. According to the method, the original fisheye camera image can be subjected to ortho-rectification, the serious distortion problem of the fisheye camera image is solved, and the large-scale ortho-image can be quickly obtained by adopting the fisheye camera in a narrow space area.

Description

technical field [0001] The invention relates to the field of computer graphics processing and photogrammetry, in particular to three aspects of fisheye image distortion correction, fisheye camera calibration and orthorectification. Background technique [0002] The fisheye lens camera has a wide viewing angle, and the image acquired in one shot contains more spatial information. Therefore, in recent years, research on fisheye cameras has become more and more popular internationally, and has been gradually applied in robot navigation, planetary exploration, panoramic monitoring, public security, pipeline detection, assisted driving, on-site inspection, vehicle inspection and virtual reality, etc. field. However, due to the short focal length and complex structure of the fisheye lens, the fisheye image has serious distortion, which does not conform to the central projection, let alone meet the needs of accurate measurement. Therefore, without correcting for these distortions...

AI Technical Summary

Problems solved by technology

[0005] The invention discloses a fisheye camera orthorectification correction method to solve the problem that the current fisheye camera image has serious distortion and cannot meet the needs of accurate measurement

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